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Li TM, Pien LC, Cheng WJ. Direction and magnitude of social jetlag are associated with obesity: Results from a sample of hospital employees. Chronobiol Int 2022; 39:1242-1248. [PMID: 35796193 DOI: 10.1080/07420528.2022.2090953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Social jetlag, the discrepancy between social and biological timing, has been suggested to disturb metabolic functions. However, the relationship between social jetlag and obesity has been inconsistent in other studies. In this study we examined the association between social jetlag and obesity among day and shift workers. We invited 2508 day workers and 1383 shift workers from a hospital worker health cohort to participate in a 2018-2019 survey on their sleep behaviors. Shift-specific social jetlag was quantified using the Munich ChronoType Questionnaire, and body mass index was measured during annual physical examinations. The distributions of shift-specific social jetlag were illustrated, and logistic regression analysis was used to examine the association between social jetlag and obesity. We found that high level of social jetlag (odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.08-1.47) and positive social jetlag (OR = 2.25, 95% CI = 1.30-3.90) during evening shifts were associated with obesity after adjustment for age, sex, health behaviors, and sleep quality. During night shift periods, sleep time varied greatly on free days, but the participants slept at similar times, namely 16:00, on workdays. In conclusion, phase advance on workdays and high levels of social jetlag were associated with obesity. Sleep timing should therefore be recommended according to the relative phase of individuals' preferred sleep time and work time.
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Affiliation(s)
- Tin-May Li
- Department of Psychiatry, Taichung Prison Pei-Teh Hospital, Taichung, Taiwan.,Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Li-Chung Pien
- Program in Nursing, College of Nursing, Taipei Medical UniversityPost-Baccalaureate, Taipei, Taiwan
| | - Wan-Ju Cheng
- Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan.,Department of Public Health, China Medical University, Taichung, Taiwan
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2
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A Growing Link between Circadian Rhythms, Type 2 Diabetes Mellitus and Alzheimer's Disease. Int J Mol Sci 2022; 23:ijms23010504. [PMID: 35008933 PMCID: PMC8745289 DOI: 10.3390/ijms23010504] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 12/29/2021] [Accepted: 12/31/2021] [Indexed: 02/04/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) patients are at a higher risk of developing Alzheimer’s disease (AD). Mounting evidence suggests the emerging important role of circadian rhythms in many diseases. Circadian rhythm disruption is considered to contribute to both T2DM and AD. Here, we review the relationship among circadian rhythm disruption, T2DM and AD, and suggest that the occurrence and progression of T2DM and AD may in part be associated with circadian disruption. Then, we summarize the promising therapeutic strategies targeting circadian dysfunction for T2DM and AD, including pharmacological treatment such as melatonin, orexin, and circadian molecules, as well as non-pharmacological treatments like light therapy, feeding behavior, and exercise.
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3
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Sargent C, Kosmadopoulos A, Zhou X, Roach GD. Timing of Sleep in the Break Between Two Consecutive Night-Shifts: The Effect of Different Strategies on Daytime Sleep and Night-Time Neurobehavioural Function. Nat Sci Sleep 2022; 14:231-242. [PMID: 35210890 PMCID: PMC8860456 DOI: 10.2147/nss.s336795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE The aim of this study was to examine whether the timing of sleep in the break between consecutive night-shifts affects the quantity and quality of sleep obtained during the daytime and/or neurobehavioural function and self-perceived capacity during the night-time. METHODS Participants (n = 12, all male, aged 22.9±5.2 y) completed three randomised, counterbalanced conditions in a sleep laboratory, consisting of two consecutive 12-hour night-shifts (18:00-06:00) with 7 hours in bed in the break between shifts. The three conditions differed only in the timing of the sleep opportunities - immediate (07:00-14:00), delayed (10:00-17:00), split (07:00-10:30 and 13:30-17:00). Neurobehavioural function (attention, memory, throughput) and self-perceived capacity (sleepiness, alertness, fatigue, mood) were assessed at 2-hour intervals during the night-shifts. RESULTS Condition did not affect total sleep time (p = 0.465), but it did affect sleep onset latency (p < 0.001; W = 0.780; large effect), wake after sleep onset (p = 0.018; W = 0.333; moderate effect) and the amount of Stage N3 sleep (p < 0.001; η2=0.510; small effect). Compared to the immediate and delayed sleep conditions, the split sleep condition had less wake after sleep onset and more Stage N3 sleep; and compared to the delayed condition, the split sleep condition had longer latency to sleep onset. There was no effect of condition on measures of neurobehavioural function or self-perceived capacity during the second night-shift. CONCLUSION None of the three sleep strategies examined here - immediate, delayed or split - are clearly superior or inferior to the others in terms of the capacity to sleep during the daytime or to work at night. Therefore, those who work consecutive night-shifts should employ the strategy that best suits their personal preferences and/or circumstances.
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Affiliation(s)
- Charli Sargent
- Appleton Institute for Behavioural Science, Central Queensland University, Wayville, SA, Australia
| | - Anastasi Kosmadopoulos
- Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Xuan Zhou
- Centre for Quantitative Genetics and Genomics, Aarhus University, Aarhus, Denmark
| | - Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, Wayville, SA, Australia
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4
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Cavalheiri JC, Pascotto CR, Tonini NS, Vieira AP, Ferreto LED, Follador FAC. Sleep quality and common mental disorder in the hospital Nursing team. Rev Lat Am Enfermagem 2021; 29:e3444. [PMID: 34468620 PMCID: PMC8432590 DOI: 10.1590/1518-8345.4280.3444] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
Objective: to determine the prevalence of sleep quality and common mental disorder in
Nursing professionals and factors associated with sleep change. Method: a cross-sectional, analytical and quantitative study developed with 196
Nursing professionals of a public hospital and a mixed one. Data was
collected by means of an instrument of sociodemographic characterization, by
the Self-Report Questionnaire 20 and Pittsburgh Sleep Quality Index and were
analyzed by descriptive and inferential statistics to identify possible
factors associated with sleep changes. Results: sleep changes were identified among the Nursing professionals with a
frequency of 76.5% (70.4-82.1). Sleep quality was classified as poor in
41.8% (41.8-55.6) and sleep disorder in 27.6%. (21.4-34.2). The prevalence
of common mental disorder was identified in 36.7% (30.1-43.9). The main
factor for poor sleep quality was the presence of common mental disorder
(Odds Ratio: 5.15; p<0.001). Conclusion: sleep changes were prevalent and the characteristics of the work environment
and the presence of mental disorder showed relevance in the changes.
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Affiliation(s)
| | | | | | - Ana Paula Vieira
- Universidade Estadual do Oeste do Paraná, Francisco Beltrão, PR, Brazil
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5
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No Effect of Chronotype on Sleepiness, Alertness, and Sustained Attention during a Single Night Shift. Clocks Sleep 2021; 3:377-386. [PMID: 34287273 PMCID: PMC8293041 DOI: 10.3390/clockssleep3030024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/05/2021] [Accepted: 06/21/2021] [Indexed: 11/20/2022] Open
Abstract
The study’s aim was to examine the effect of chronotype on cognitive performance during a single night shift. Data were collected from 72 (36f) young, healthy adults in a laboratory study. Participants had a 9 h sleep period (03:00–12:00) followed by an 8 h night shift (23:00–07:00). During the night shift, participants completed five test sessions, which included measures of subjective sleepiness, subjective alertness, and sustained attention (i.e., psychomotor vigilance task; PVT). Dim light melatonin onset (DLMO) was derived from saliva samples taken during the evening preceding the night shift. A tertile split of DLMO was used to determine three chronotype categories: earlier (DLMO = 20:22 ± 0:42), intermediate (DLMO = 21:31 ± 0:13), and later (DLMO = 22:54 ± 0:54). There were (a) significant main effects of test session (all p < 0.001); (b) no main effects of chronotype; and (c) no interaction effects between chronotype and test session on sleepiness, alertness, PVT response time, and PVT lapses. The results indicate that under controlled sleeping conditions, chronotype based on dim light melatonin onset did not affect nighttime performance. Differences in performance during night shift between chronotypes reported by field studies may be related to differences in the amount and/or timing of sleep before or between night shifts, rather than circadian timing.
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6
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Association between chronotype and psychomotor performance of rotating shift workers. Sci Rep 2021; 11:6919. [PMID: 33767333 PMCID: PMC7994306 DOI: 10.1038/s41598-021-86299-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/05/2021] [Indexed: 12/22/2022] Open
Abstract
It is known that the chronotype potentially mediates the performance and tolerance to work in shifts and that shift rotation is associated with negative effects on psychomotor performance. This study aimed to evaluate the effect of chronotype on psychomotor performance throughout a complete shift rotation schedule. Thirty males working in clockwise rotating shifts from a mining company were evaluated under a real-life condition over the following shift schedule: 2 days of day work, 2 days of evening work and 2 days of night work. The chronotype was determined using the Munich Chronotype Questionnaire adapted for shift workers and the obtained scores were categorized by tertiles (early-type, intermediate-type and late-type). Work performance was evaluated by Psychomotor Vigilance Test (PVT) daily just before shift starts and after shift ends. Sleep duration was evaluated by actigraphy over the whole shift. No isolated effect of the shift or interaction between shift and chronotype was found in the performance variables evaluated. A significant isolated effect of the chronotype showed that the early-type individuals had higher values of pre- and post-work Mean of Reaction Time (MRT) (308.77 ± 10.03 ms and 306.37 ± 8.53 ms, respectively) than the intermediate-type (257.61 ± 6.63 ms and 252.91 ± 5.97 ms, respectively, p < 0.001) and the late-type (273.35 ± 6.96 ms and 262.88 ± 6.05 ms, respectively, p < 0.001). In addition, late individuals presented a greater number of lapses of attention (5.00 ± 0.92; p < 0.05) than early (1.94 ± 0.50, p < 0.05) and intermediate (1.33 ± 0.30, p < 0.001) ones. We concluded that, compared with intermediates, late-type workers had a greater number of lapses of attention on the shift schedule as a whole, while early-type workers showed the highest pre- and post-work MRT. These findings show that the psychomotor performance of rotating shift workers seems to be influenced by the chronotype, but not by the shift rotation.
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7
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Bjorvatn B, Pallesen S, Waage S, Thun E, Blytt KM. The effects of bright light treatment on subjective and objective sleepiness during three consecutive night shifts among hospital nurses - a counter-balanced placebo-controlled crossover study. Scand J Work Environ Health 2020; 47:145-153. [PMID: 33080034 PMCID: PMC8114564 DOI: 10.5271/sjweh.3930] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Objectives The objective was to investigate effects of timed bright light treatment on subjective and objective measures of sleepiness during three consecutive night shifts among hospital nurses. Methods Thirty-five nurses were exposed to bright light (10,000 lux) and red dim light (100 lux) during three consecutive night shifts in a counter-balanced crossover trial lasting nine days, which included three days before and three days after the three night shifts. Light exposure for 30 minutes was scheduled between 02:00-03:00 hours on night 1, and thereafter delayed by one hour per night in order to delay the circadian rhythm. Subjective sleepiness was measured daily (heavy eyelids, reduced performance) and every second hour while awake (Karolinska Sleepiness Scale, KSS). Objective sleepiness (Psychomotor Vigilance Task, PVT) was measured at 05:00 hours during each night shift. Beyond nocturnal light exposure on the night shifts, no behavioral restrictions or recommendations were given at or off work. Results Bright light treatment significantly reduced heavy eyelids during night shifts. However, results on KSS and PVT were unaffected by bright light. There were no differences in subjective sleepiness during the three days following the night shifts. Conclusions This bright light treatment protocol did not convincingly reduce sleepiness among nurses during three consecutive night shifts. Nor did bright light impede the readaptation back to a day-oriented rhythm following the night shift period. Too few consecutive night shifts, inappropriate timing of light, and possible use of other countermeasures are among the explanations for the limited effects of bright light in the present study.
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Affiliation(s)
- Bjørn Bjorvatn
- Department of Global Public Health and Primary Care, University of Bergen, Kalfarveien 31, N-5018 Bergen, Norway.
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8
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St Hilaire MA, Lammers-van der Holst HM, Chinoy ED, Isherwood CM, Duffy JF. Prediction of individual differences in circadian adaptation to night work among older adults: application of a mathematical model using individual sleep-wake and light exposure data. Chronobiol Int 2020; 37:1404-1411. [PMID: 32893681 DOI: 10.1080/07420528.2020.1813153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Circadian misalignment remains a distinct challenge for night shift workers. Variability in individual sleep-wake/light-dark patterns might contribute to individual differences in circadian alignment in night shift workers. In this simulation study, we compared the predicted phase shift from a mathematical model of the effect of light on the human circadian pacemaker to the observed melatonin phase shift among individuals who completed one of four interventions during simulated night shift work. Two inputs to the model were used to simulate circadian phase: sleep-wake/light-dark patterns measured from a wrist monitor (Simulation 1) and sleep-wake/light-dark patterns measured from a wrist monitor enhanced by known light levels measured at the level of the eye during simulated night shifts (Simulation 2). The estimated phase shift from the model was within 2 hours of the observed phase shift in ~80% of night shift workers for both simulations; none of the model-predicted phase shifts was more than ~3 hours from the observed phase shift. Overall, the root-mean-square error between observed and predicted phase shifts was better for Simulation 1. The light input from the wrist monitor informed by actual light level measured at the eye performed better in the sub-group exposed to bright light during their night shifts. The findings from this simulation study suggest that using a mathematical model combined with sleep-wake and light exposure data from a wrist monitor can facilitate the design of shift work schedules to enhance circadian alignment, which is expected to improve sleep, alertness, and performance.
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Affiliation(s)
- Melissa A St Hilaire
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Heidi M Lammers-van der Holst
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Evan D Chinoy
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Cheryl M Isherwood
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
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9
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Isherwood CM, Chinoy ED, Murphy AS, Kim JH, Wang W, Duffy JF. Scheduled afternoon-evening sleep leads to better night shift performance in older adults. Occup Environ Med 2020; 77:179-184. [PMID: 31949042 DOI: 10.1136/oemed-2019-105916] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 10/08/2019] [Accepted: 11/03/2019] [Indexed: 01/20/2023]
Abstract
OBJECTIVES This study investigated whether an intervention designed to reduce homeostatic sleep pressure would improve night shift performance and alertness in older adults. METHODS Non-shift workers aged 57.9±4.6 (mean±SD) worked four day (07:00-15:00) and four night shifts (23:00-07:00). Two intervention groups were instructed to remain awake until ~13:00 after each night shift: the sleep timing group (ST; n=9) was instructed to spend 8 hours in bed attempting sleep, and the sleep ad-lib group (n=9) was given no further sleep instructions. A control group (n=9) from our previous study was not given any sleep instructions. Hourly Karolinska Sleepiness Scales and Psychomotor Vigilance Tasks assessed subjective sleepiness and performance. RESULTS The ST group maintained their day shift sleep durations on night shifts, whereas the control group slept less. The ST group were able to maintain stable performance and alertness across the initial part of the night shift, while the control group's alertness and performance declined across the entire night. Wake duration before a night shift negatively impacted sustained attention and self-reported sleepiness but not reaction time, whereas sleep duration before a night shift affected reaction time and ability to sustain attention but not self-reported sleepiness. CONCLUSIONS A behavioural change under the control of the individual worker, spending 8 hours in bed and waking close to the start of the night shift, allowed participants to acquire more sleep and improved performance on the night shift in older adults. Both sleep duration and timing are important factors for night shift performance and self-reported sleepiness.
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Affiliation(s)
- Cheryl Martine Isherwood
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Evan D Chinoy
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Audra S Murphy
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Jee Hyun Kim
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurology, Dankook University College of Medicine, Dankook University Hospital, Cheonan, Republic of Korea
| | - Wei Wang
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA .,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
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10
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Shift rotation, circadian misalignment and excessive body weight influence psychomotor performance: a prospective and observational study under real life conditions. Sci Rep 2019; 9:19333. [PMID: 31852906 PMCID: PMC6920148 DOI: 10.1038/s41598-019-55114-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 11/13/2019] [Indexed: 01/28/2023] Open
Abstract
We aimed to evaluate the influence of shift work rotation, circadian misalignment and being overweight/obese on psychomotor performance throughout a complete shift rotation schedule. The study was conducted with 30 males working rotating shifts from a mining company under real life conditions. Individuals were evaluated over seven days in a shift schedule carried out as follow: two shifts in the morning (D1 and D2), two shifts in the afternoon (D3 and D4), 24 hour free day (D5) and two shifts at night (D6 and D7). Work performance was evaluated by psychomotor vigilance task tests (PVT), and actigraphy was used to characterise the rest-activity rhythm based on intradaily variability (IV) and interdaily stability (IS) of nonparametric functions. We found a significant effect of the shift, body mass index (BMI), IS and IV on lapses in attention. More lapses occurred on D7 than D1, D2, D3 and D4 of the schedule shift. The obese group presented a higher number of lapses in attention than eutrophic. The interaction between day and IS showed that less synchronised individuals presented a higher number of lapses in attention on D7 than D1 and, for the interaction between day and IV, more fragmented individuals presented a higher number of lapses in attention on D7 than D6. We conclude that higher BMI, lower synchronisation and higher fragmentation of the rest-activity pattern influenced lapses in attention throughout the shift rotation.
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11
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McHill AW, Wright KP. Cognitive Impairments during the Transition to Working at Night and on Subsequent Night Shifts. J Biol Rhythms 2019; 34:432-446. [PMID: 31072264 DOI: 10.1177/0748730419848552] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Demands of modern society force many work operations into the night when the internal circadian timekeeping system is promoting sleep. The combination of disturbed daytime sleep and circadian misalignment, which is common in overnight shift work, decreases cognitive performance, yet how performance may differ across multiple consecutive nights of shift work is not fully understood. Therefore, the primary aim of this study was to use a simulated night-shift protocol to examine the cognitive performance and ratings of sleepiness and clear-headedness across the hours of a typical daytime shift, a first night shift with an afternoon nap and extended wakefulness, and 2 subsequent overnight shifts. We tested the hypothesis that cognitive performance would be worse on the first night shift as compared with the baseline and subsequent nighttime shifts and that performance during nighttime shifts would be reduced as compared with the baseline daytime shift. Fifteen healthy adults (6 men) were studied in the 6-day in-laboratory protocol. Results showed that working during the night increased subjective sleepiness and decreased clear-headedness and performance on the Psychomotor Vigilance Task (i.e., slower median, fastest and slowest reaction times, and increased attentional lapses), Stroop color word task (decreased number of correct responses and slower median reaction time), and calculation addition performance task (decreased number attempted and correct). Furthermore, we observed limited evidence of sleepiness, clear-headedness, or performance adaptation across subsequent nights of simulated night work. Our findings demonstrate that night-shift work, regardless of whether it is the first night shift with a nap and extended wakefulness or subsequent night shifts, decreases performance and clear-headedness as compared with the day shift.
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Affiliation(s)
- Andrew W McHill
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, Oregon
| | - Kenneth P Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
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12
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Ganesan S, Magee M, Stone JE, Mulhall MD, Collins A, Howard ME, Lockley SW, Rajaratnam SMW, Sletten TL. The Impact of Shift Work on Sleep, Alertness and Performance in Healthcare Workers. Sci Rep 2019; 9:4635. [PMID: 30874565 PMCID: PMC6420632 DOI: 10.1038/s41598-019-40914-x] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 02/19/2019] [Indexed: 01/19/2023] Open
Abstract
Shift work is associated with impaired alertness and performance due to sleep loss and circadian misalignment. This study examined sleep between shift types (day, evening, night), and alertness and performance during day and night shifts in 52 intensive care workers. Sleep and wake duration between shifts were evaluated using wrist actigraphs and diaries. Subjective sleepiness (Karolinska Sleepiness Scale, KSS) and Psychomotor Vigilance Test (PVT) performance were examined during day shift, and on the first and subsequent night shifts (3rd, 4th or 5th). Circadian phase was assessed using urinary 6-sulphatoxymelatonin rhythms. Sleep was most restricted between consecutive night shifts (5.74 ± 1.30 h), consecutive day shifts (5.83 ± 0.92 h) and between evening and day shifts (5.20 ± 0.90 h). KSS and PVT mean reaction times were higher at the end of the first and subsequent night shift compared to day shift, with KSS highest at the end of the first night. On nights, working during the circadian acrophase of the urinary melatonin rhythm led to poorer outcomes on the KSS and PVT. In rotating shift workers, early day shifts can be associated with similar sleep restriction to night shifts, particularly when scheduled immediately following an evening shift. Alertness and performance remain most impaired during night shifts given the lack of circadian adaptation to night work. Although healthcare workers perceive themselves to be less alert on the first night shift compared to subsequent night shifts, objective performance is equally impaired on subsequent nights.
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Affiliation(s)
- Saranea Ganesan
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Michelle Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Julia E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Megan D Mulhall
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Mark E Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Shantha M W Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Tracey L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia. .,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.
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13
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Griepentrog JE, Labiner HE, Gunn SR, Rosengart MR. Bright environmental light improves the sleepiness of nightshift ICU nurses. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2018; 22:295. [PMID: 30424793 PMCID: PMC6234544 DOI: 10.1186/s13054-018-2233-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/15/2018] [Indexed: 12/21/2022]
Abstract
Background Shift work can disturb circadian homeostasis and result in fatigue, excessive sleepiness, and reduced quality of life. Light therapy has been shown to impart positive effects in night shift workers. We sought to determine whether or not prolonged exposure to bright light during a night shift reduces sleepiness and enhances psychomotor performance among ICU nurses. Methods This is a single-center randomized, crossover clinical trial at a surgical trauma ICU. ICU nurses working a night shift were exposed to a 10-h period of high illuminance (1500–2000 lx) white light compared to standard ambient fluorescent lighting of the hospital. They then completed the Stanford Sleepiness Scale and the Psychomotor Vigilance Test. The primary and secondary endpoints were analyzed using the paired t test. A p value <0.05 was considered significant. Results A total of 43 matched pairs completed both lighting exposures and were analyzed. When exposed to high illuminance lighting subjects experienced reduced sleepiness scores on the Stanford Sleepiness Scale than when exposed to standard hospital lighting: mean (sem) 2.6 (0.2) vs. 3.0 (0.2), p = 0.03. However, they committed more psychomotor errors: 2.3 (0.2) vs. 1.7 (0.2), p = 0.03. Conclusions A bright lighting environment for ICU nurses working the night shift reduces sleepiness but increases the number of psychomotor errors. Trial registration ClinicalTrials.gov, NCT03331822. Retrospectively registered on 6 November 2017.
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Affiliation(s)
- John E Griepentrog
- Department of Surgery, University of Pittsburgh, 200 Lothrop Street - Suite F1266.1, Pittsburgh, PA, 15213, USA
| | - Hanna E Labiner
- Department of Surgery, University of Pittsburgh, 200 Lothrop Street - Suite F1266.1, Pittsburgh, PA, 15213, USA
| | - Scott R Gunn
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew R Rosengart
- Department of Surgery, University of Pittsburgh, 200 Lothrop Street - Suite F1266.1, Pittsburgh, PA, 15213, USA. .,Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Paech GM, Crowley SJ, Fogg LF, Eastman CI. Advancing the sleep/wake schedule impacts the sleep of African-Americans more than European-Americans. PLoS One 2017; 12:e0186887. [PMID: 29059251 PMCID: PMC5653363 DOI: 10.1371/journal.pone.0186887] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 10/09/2017] [Indexed: 12/16/2022] Open
Abstract
There are differences in sleep duration between Blacks/African-Americans and Whites/European-Americans. Recently, we found differences between these ancestry groups in the circadian system, such as circadian period and the magnitude of phase shifts. Here we document the role of ancestry on sleep and cognitive performance before and after a 9-h advance in the sleep/wake schedule similar to flying east or having a large advance in sleep times due to shiftwork, both of which produce extreme circadian misalignment. Non-Hispanic African and European-Americans (N = 20 and 17 respectively, aged 21-43 years) were scheduled to four baseline days each with 8 h time in bed based on their habitual sleep schedule. This sleep/wake schedule was then advanced 9 h earlier for three days. Sleep was monitored using actigraphy. During the last two baseline/aligned days and the first two advanced/misaligned days, beginning 2 h after waking, cognitive performance was measured every 3 h using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Mixed model ANOVAs assessed the effects of ancestry (African-American or European-American) and condition (baseline/aligned or advanced/misaligned) on sleep and cognitive performance. There was decreased sleep and impaired performance in both ancestry groups during the advanced/misaligned days compared to the baseline/aligned days. In addition, African-Americans obtained less sleep than European-Americans, especially on the first two days of circadian misalignment. Cognitive performance did not differ between African-Americans and European-Americans during baseline days. During the two advanced/misaligned days, however, African-Americans tended to perform slightly worse compared to European-Americans, particularly at times corresponding to the end of the baseline sleep episodes. Advancing the sleep/wake schedule, creating extreme circadian misalignment, had a greater impact on the sleep of African-Americans than European-Americans. Ancestry differences in sleep appear to be exacerbated when the sleep/wake schedule is advanced, which may have implications for individuals undertaking shiftwork and transmeridian travel.
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Affiliation(s)
- Gemma M. Paech
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Stephanie J. Crowley
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Louis F. Fogg
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Charmane I. Eastman
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
- * E-mail:
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